The Hal RS2100 RTTY scope is an accessory that can be used with RTTY decoders such as the CWR-6700. The RS2100 makes precisely tuning RTTY a snap. It features a one inch diameter, green phosphore CRT. Separate phono inputs on the back panel are provided for horizontal [Mark] and vertical [Space] inputs. The RS2100 also features a 175 volt, 60 ma loop supply to support teleprinter machines.